Projected studies include: (1) Purification and general characterization of proline hydroxylase from earthworm subcuticular epithelium. (2) Studies of the specificity of proline hydroxylation by the earthworm enzyme. (3) Metabolism of 3-hydroxyproline in mammals and bacteria. (4) Sequence studies on 3-hydroxyproline in various collagens. (5) Synthesis of collagen-like polypeptides containing proline, 4-hydroxyproline or 3-hydroxyproline.